The present invention relates to apparatus for introducing stacks of paper sheets or the like into containers, e.g., into boxes made of thick paper, cardboard or similar material.
It is already known to fill containers (hereinafter called boxes for short) in an apparatus wherein a receptacle for stacks of paper sheets has an open side for introduction of stacks into its interior and is vertically movable between a raised position in which it receives a stack of sheets from a suitable conveyor or the like and a lower position in which it is ready to discharge its contents into a box therebelow. As a rule, the conveyor which supplies stacks delivers successive stacks into a position of abutment with a stop, whereupon a pusher transfers the arrested stack into the receptacle. The bottom of the receptacle consists of two flaps which are pivotably secured to the respective side walls and can be moved between substantially horizontal positions in which they support the stack from below and substantially vertical positions in which they extend into the interior of an empty box when the receptacle is moved to its lower position. The flaps constitute a gate and further serve to guide the descending stack into the interior of the box which is located below and registers with the receptacle.
A drawback of the just described apparatus is that it cannot be used for introduction of stacks into boxes which are dimensioned to receive the stacks without any or with negligible clearance. Furthermore, many types of boxes are rather unstable and tend to undergo pronounced deformation during introduction of stacks. If the side walls of the boxes are deformable, such side walls tend to bulge outwardly during introduction of stacks whereby the upstanding corners of the box move inwardly and prevent the corners of the stack from entering the box. The flaps reduce the likelihood of excessive bulging of at least two side walls because they extend into the interior of the box below the receptacle. However, they interfere with immediate removal of a filled box from a position of register with the receptacle. Furthermore, the receptacle cannot receive a fresh stack prior to return movement to raised position to thereby extract the flaps from the filled box therebelow and prior to subsequent pivoting of the flaps back to their normal stack-supporting positions. The filled box can be replaced with an empty box when the receptacle is raised and its flaps returned to stack-supporting positions. Therefore, the output of the just described apparatus cannot be increased to the extent which is necessary to warrant economic operation of a modern production line wherein the sheets are severed and stacked at an extremely high speed.